A couple ?'s about macs and a Windows 2003 Server

I have a Windows 2003 Server setup as a file and print server for 4-5 Macs and 4-5 PCs. All these users will soon be on Macs, with no PCs.

1.) Can all these Macs use the file/print server as is, and is there a 4GB file size limit?
2.) All these users will also need to use some kind of Terminal Services application to access one single application that also runs on that server.....Is it possible to set something like that up? So each user would have a shortcut icon on their desktop and it would open up to JUST that application without giving them access to the rest of the server/file system?